1. Field of the Invention
The present invention relates generally to the field of photography and more specifically to a method and apparatus for analyzing captured digital images.
2. Description of the Prior Art
FIG. 1 provides a cross-section of a digital Single Lens Reflex (SLR) camera 100 of the prior art. The digital SLR camera 100 includes a housing 102 and a lens system 104 that in most designs is removable. The lens system 104 includes focusing optics 106 that direct incoming light along an optical axis 108. A sensor 110 intersects, and is typically centered on, the optical axis 108 opposite the lens system 104 along a focal plane thereof.
The sensor 110 typically consists of an array of photosensitive pixel sensors that are each capable of converting incident light into an electric signal. Image capturing electronics create a digital image by digitizing the electric signals from each of the pixel sensors of the sensor 110, processing the digitized data, and storing the resulting processed data to a memory device (not shown) such as a Random Access Memory (RAM) or a magnetic disk. The digital image is typically stored as an array of pixels, where each pixel includes color and brightness information for a particular location in the digital image.
Commonly, camera 100 includes a display device 112, such as a liquid crystal display (LCD), to allow a user 114 to review captured digital images. Processing electronics 116 are provided to process captured digital images in order to generate the displayed images shown on the display device 112. Although the captured digital images are typically of a high resolution, the displayed images tend to be of a lower resolution. The difference in resolution can be caused by several factors. For example, the number of pixels in the display device 112 devoted to displaying an image is typically far fewer than the number of pixels of the full digital image. Additionally, a pixel in a display device 112 is typically unable to display as many gradations in brightness as can be represented by a pixel in the captured image. Accordingly, it can be difficult for a user 114 to judge the quality of a captured digital image from a displayed image as viewed on the display device 112.
Accordingly, what is needed is an apparatus and method that will allow a user of a digital camera to evaluate a captured digital image to determine whether the digital image is satisfactory or whether the digital image should be retaken, for example, with a different exposure setting.